1. Field of the Invention
The present invention relates to an assembly for holding guard rails at the peripheral edge of an elevated floor slab during construction of a multifloor building.
2. Description of the Prior Art
In the construction industry commercial, industrial and multiunit residential buildings are typically constructed with a framework formed of steel girders. As the framework for the various floor levels is formed, concrete floor slabs are poured so that the workmen on the project have floor support upon which to perform their tasks. Since the floor slabs are poured before the building walls are constructed it is important to create some type of perimeter guard at the edges of the floor slabs to prevent workmen from inadvertently falling off of the edge of a floor slab without realizing they are near the edge.
For many years perimeter guards for floor slabs in a multistory building have been provided by installing temporary stanchions or posts at spaced intervals around the perimeter of an elevated floor slab. The posts or stanchions are provided with cradles to receive guard rails that provide a temporary fence around the perimeter of the floor slab. This temporary boundary serves to prevent accidental falls until the building walls are constructed.
In conventional systems the installation of perimeter guard posts or stanchions requires an excessive amount of bending, stooping and manipulation of fasteners beyond the outboard edge of a floor slab by the workmen who install the guard posts. Fastening and clamping the fixtures in conventional construction perimeter guard systems require the workmen to perform tasks from awkward, dangerous positions. Also, the components are situated so that the workmen have very poor leverage when tightening the fastening elements of the perimeter guard. As a consequence, installation of a construction area perimeter guard about an elevated floor slab is quite time-consuming and labor-intensive. Furthermore, fasteners are sometimes not tightened correctly due to the poor leverage that the installing workmen are able to exert and also due to fatigue from working in awkward positions.
The present invention provides an improved construction perimeter guard system. The construction perimeter guard of the present invention employs a plurality of elongated, upright outboard support members each formed of tubular steel having a square or rectangular cross section and having a plurality of pin receiving apertures defined therethrough at spaced vertical intervals. A bottom jaw is secured to the lower extremity of the outboard support member and extends perpendicular thereto laterally inwardly to contact the underside of a concrete slab floor at its edge.
A hollow, coarse adjustment sleeve formed of a short section of tubular steel is disposed in sliding engagement relative to the outboard support member at the lower portion thereof. The coarse jaw adjustment sleeve is formed of a short section of hollow steel tubing having a square or rectangular cross section coaxially disposed about the outboard support member, in sliding engagement therewith. The coarse jaw adjustment sleeve has one or more perforations therethrough so that a locking pin can be passed through it and through aligned openings in the outboard support member.
The coarse adjustment sleeve has a laterally extending connector tube that is secured to a hollow, upright, elongated inboard rail support tube. The rail support tube is provided with at least one rail support cradle. Preferably, the inboard rail support tube has a pair of concave upwardly directed cradles designed to receive horizontally disposed guard rails about the perimeter of the concrete slab floor. The coarse adjustment sleeve is located parallel to and secured alongside the hollow, upright, inboard rail support tube.
A hollow tubular slide is provided with an upper jaw that is oriented perpendicular to the slide and attached to the lower extremity of the slide. Together the slide and upper jaw form an inboard clamp element. The slide fits telescopically within the lower end of the inboard rail support tube. Transversely extending angle sections are secured to the ends of both the upper and lower jaws.
An inner, vertically oriented fine positioning adjustment member is disposed coaxially within the upright, inboard, rail support tube. The lower extremity of the fine positioning adjustment member is secured by a screw connection to the slide, and thereby to the upper jaw. Consequently, rotational movement of the fine positioning adjustment member within the upright rail support tube moves the upper jaw closer to or further from the lower jaw.
The fine adjustment member is formed of an elongated pipe having a short threaded steel rod with an exposed length of about one and a quarter inches at its upper extremity and a longer threaded steel rod with an exposed length of about ten inches at its lower extremity. The two threaded rod sections have left handed threads and are threadably engaged with internal threads in the opposing ends of the pipe. The threaded rods are plug welded to the opposing ends of the pipe to immobilize them relative to the pipe. The pipe and threaded sections are then inserted up into the upright, inboard, rail support tube from the lower extremity thereof. The short, upper steel coupling rod projects through a bearing plate at the top of the upright rail support tube. A butterfly handle is then secured to the upper, short threaded portion of the coupling rod protruding from the top of the rail support tube.
An internally threaded nut is captured between vertically spaced rings that are welded to the inside of the slide near its upper end. The upper end of the slide is inserted up into the lower end of the rail support tube. The lower end of the longer threaded rod section is then screwed into the internally threaded nut located within the slide, thereby drawing the slide telescopically upwardly into the inboard, rail support tube.
To operate the device the upper and lower jaws are first respectively positioned to embrace the upper and lower surfaces of a building floor slab at the slab edge with the jaws as close to each other as possible and as close to the upper and lower surfaces of the concrete slab as possible, as permitted by the spacing of the vertical openings in the sleeve and in the outboard support tube. A coarse adjustment locking pin is then inserted through openings in the opposing walls of the coarse positioning sleeve and through corresponding, longitudinally aligned openings in the outboard support tube encompassed therewithin.
The butterfly handle is then rotated to advance the nut entrapped within the slide downwardly along the length of the lower threaded rod, thereby pushing the slide and upper jaw downwardly. The jaws are thereby clamped against the opposing upper and lower surfaces of the edge of the floor slab to anchor both the outboard support and the inboard rail support tube relative thereto. A plurality of stanchions are installed in this manner at spaced intervals around the perimeter of the floor. The stanchions thereby provide stable support for the transversely extending rails to form a perimeter boundary about the edge of the floor.
One principal advantage of the improved perimeter guard post of the present invention is that the operation of the fine positioning mechanism is performed by manipulating the butterfly handle at the top of the upright, inboard, rail support tube. The workman thereby does not have to stoop over to operate a clamp that is located down near the concrete slab.
In one broad aspect the present invention may be considered to be a perimeter guard rail post. The rail post of the invention is comprised of an outboard clamp element, an inboard support member, a coarse adjustment locking pin, an inboard clamp element and an elongated, fine adjustment member. The outboard clamp element includes a lower, laterally projecting jaw and an upright, elongated outboard support rigidly joined to the lower jaw and having a series of longitudinally spaced locking openings therein.
The inboard support member includes a hollow, inboard rail support tube having opposing upper and lower ends. The inboard rail support tube is provided with at least one rail cradle. The inboard support member also includes a hollow, coarse adjustment sleeve with opposing walls oriented parallel to the rail support tube and rigidly anchored alongside the rail support tube. The coarse adjustment sleeve has at least one set of locking openings therein defined through the opposing walls thereof. The coarse adjustment locking pin passes through the outboard support and the through the coarse adjustment sleeve by releaseable engagement in selected locking openings in the outboard support and the coarse adjustment sleeve.
The inboard clamp element includes a laterally projecting upper jaw and a slide rigidly secured to the upper jaw and extending upwardly therefrom into the lower end of the inboard rail support tube. The slide has an internally tapped member longitudinally immobilized relative thereto.
The elongated, fine adjustment member has opposing upper and lower ends and is disposed within the rail support tube. The fine adjustment member has an externally threaded element at its lower end threadably engaged with the internally tapped member and at least one drive lever at its upper end. The upper end of the rail support tube has a transverse bearing plate with an opening therethrough. The upper end of the fine adjustment member passes through the opening in the bearing plate and is rotatable therewithin. The upper end of the fine adjustment member is longitudinally constrained by the bearing plate. Consequently, rotation of the fine adjustment member by means of the drive lever in opposing directions longitudinally advances and retracts the slide relative to the rail support tube.
Preferably the outboard support, the rail support tube, the coarse adjustment sleeve and the slide are all formed of sections of hollow steel tubing having square cross sections. Also, the internally tapped member of the slide is preferably a nut captured between a pair of abutment rings secured within the slide. In this way the abutment rings restrain the nut from any significant longitudinal movement within the slide, yet allow the nut to be aligned properly for engagement with the fine adjustment member.
The elongated fine adjustment member is preferably comprised of an elongated hollow, cylindrical pipe having opposing internally threaded upper and lower ends and an externally threaded fine adjustment rod having a length at least as great as the distance between the spaced locking openings in the outboard support. The externally threaded fine adjustment rod is threadably engaged in the lower end of the cylindrical pipe and is immobilized from rotation relative thereto, preferably by a weld. The fine adjustment member is further preferably comprised of an externally threaded coupling rod threadably engaged in the upper end of the cylindrical pipe. The coupling rod is also immobilized relative to the pipe, preferably by welding.
The coupling rod extends through the bearing plate and protrudes from the upper end of the rail support tube. The drive lever is preferably formed of a pair of diametrically opposed lever arms or handles and is fastened and rigidly anchored to the coupling rod atop the rail support tube. The pair of diametrically opposed lever arms project radially from the coupling rod. A retaining nut is preferably engaged on and rigidly attached to the coupling rod above the drive lever.
The locking openings in the outboard support are longitudinally spaced no further from each other than about four inches apart and are provided over a distance of at least three feet along the length of the outboard support. The coarse adjustment sleeve preferably includes at least two sets of locking openings or apertures longitudinally spaced apart from each other a distance no greater than about two inches. The upright, rail support tube is preferably at least about three feet long so that a workman manipulating the lever arms located above the upper end of the rail support tube is not required to bend or stoop in order to perform the fine adjustment necessary to secure the perimeter guard rail post to the edge of the floor slab.
The present invention may also be considered to be a perimeter guard stanchion comprising: an outboard clamp element, an inboard support member, at least one locking pin, an inboard clamp element and an elongated fine adjustment member. The outboard clamp element includes an upright, elongated outboard support having a plurality of longitudinally spaced locking apertures defined therein and a laterally projecting lower jaw that is rigidly joined to the lower end of the outboard support. The inboard support member includes a hollow, inboard rail support tube having opposing upper and lower ends and is equipped with at least one rail cradle. A hollow, upright sleeve is oriented parallel to and is located alongside the inboard rail support tube. The upright sleeve has at least one set of locking apertures defined therethrough and is rigidly joined to the inboard rail support. The locking pin is releaseably engageable in at least one selected locking aperture in the outboard support element and in the at least one set of locking apertures in the upright sleeve.
The inboard clamp element includes a laterally projecting upper jaw and a hollow slide rigidly secured to the upper jaw. The slide extends upwardly from the upper jaw in telescopic engagement within the lower end of the rail support tube. An internally tapped member is secured to the hollow slide.
The elongated fine adjustment member has an externally threaded lower end threadably engaged in the internally tapped member and an opposite upper end longitudinally immobilized by the inboard support member. In this way the fine adjustment member is captured by and is rotatable relative to the rail support tube to advance and retract the upper jaw relative to the lower jaw.
The invention may also be considered to be a dual adjustment construction perimeter guard for gripping the edge of an elevated, horizontally disposed slab. The perimeter guard is comprised of an outboard clamp element including a horizontal lower jaw for positioning beneath the edge of the slab and an elongated outboard vertical support member rigidly joined to the lower jaw and projecting upwardly therefrom and defining a plurality of locking apertures therein spaced along its length.
An inboard support member includes an elongated, vertical rail support tube having a lower end and an opposing upper end. The rail support tube has at least one cradle thereon to receive a transverse barrier rail. The upper end of the rail support tube is closed by a transverse end plate with a central aperture therethrough. A hollow vertical sleeve is disposed alongside the lower end of the vertical tube and is rigidly joined thereto. The sleeve receives the outboard vertical support member therewithin and has at least one set of locking apertures defined therethrough. A locking pin projects through the set of locking apertures in the sleeve and through at least one selected, vertically aligned locking aperture in the outboard vertical support member.
An inboard clamp element is provided and includes a horizontal upper jaw for positioning atop the edge of the slab. A hollow, vertical slide tube projects upwardly from the upper jaw telescopically within the lower end of the rail support tube. An internally tapped member is longitudinally immobilized within the vertical slide tube. An elongated fine adjustment screw element is mounted within the vertical rail support tube and has a lower, externally threaded end threadably engaged in the internally tapped member within the vertical slide tube. The fine adjustment screw element also has an upper, externally threaded end projecting upwardly through the central aperture in the transverse end plate of the rail support tube. The upper end of the fine adjustment screw element is longitudinally immobilized relative to the rail support tube. At least one lever arm projects radially from the upper, externally threaded end of the fine adjustment screw for rotating the screw element to advance and retract the slide tube relative to the inboard rail support member.